Isoperla fulva Claassen, 1937

Sandberg, John B. & Kondratieff, Boris C., 2013, The Isoperla Of California (Plecoptera: Perlodidae); Updated Male Descriptions And Adult Keys For 18 Western Nearctic Species, Illiesia 9 (5), pp. 34-64 : 46-48

publication ID

publication LSID


persistent identifier

treatment provided by


scientific name

Isoperla fulva Claassen


Isoperla fulva Claassen

( Figs. 6 View Figs a-d, 20 View Figs b)

Isoperla fulva Claassen 1937 .

Holotype ♂, Utah, Logan River.

Male. Aedeagus: sclerotized posterior process present; body with one posterior lobe, one small dorsal lobe, and one large anterior lobe ( Fig. 6a View Figs ); one small bulbous patch of spinulae above sclerotized process ( Figs. 6 View Figs a-c); sclerotized process length approaching 0.5 mm when fully extended, blade-like in lateral view ( Fig. 6a View Figs ), distal margin expanded and slightly membranous in posterior view ( Fig. 6b View Figs ), and narrow proximal portion of sclerotized process sometimes extended past posterior aedeagal membrane ( Fig. 6a View Figs ). Abdominal terga 8-9, 9, 9-10: without stout spinulae or long stout setae. Posterolateral margins of at least abdominal segment 8 with scale-like setae clustered in brushes of several setae. Paraprocts: curved dorsally, length if straightened subequal to combined first and second cercal segments, tapering abruptly to blunt apices ( Fig. 6a View Figs ). Vesicle: rounded lobe, widest at base with broadly rounded apical margin ( Fig. 6d View Figs ).

Isoperla fulva is most similar to the two other I. marmorata complex species, I. marmorata and I. roguensis . These species differ in paraproct shape and aedeagal characters. The paraprocts taper abruptly to blunt apices in I. fulva , taper gradually to blunt apices in I. marmorata , and taper abruptly to tiny sharp apices in I. roguensis ( Table 1 View Table 1 ). The distal margin of blade-like sclerotized processes is thin in I. marmorata , expanded in I. fulva and expanded and variably-shaped in I. roguensis .

The aedeagus of this species was described with an additional pair of long narrow tubular lobes extending from the base of the anterodorsal lobe ( Szczytko & Stewart 1979, fig. 138C). When using the live eversion method, these processes remain inverted ( Fig. 6a View Figs ); however two small areas in inverted membrane are present on anterior lobe C of this study (not discernible in Fig. 6a View Figs ). The live everted aedeagus was cleared in KOH, which allowed observation of an inverted pair of tube-like processes within the aedeagus, and openings along the anteroapical margin ( Fig. 20b View Figs ). The small dorsal lobe B ( Figs. 6a & c View Figs ) in the current study possesses a pair of minute, closely placed holes from which seminal fluid streamed after live eversion and fixing. These dorsal aedeagal openings require further study before their function can be determined.

Isoperla fulva is putatively known from California based on three males and one female (El Dorado and Modoc counties - Jewett 1960) and Plumas County ( Szczytko & Stewart 1979) collected in the 1940’s and 1950’s. No recent material (everted males) from California compares well with the Colorado and Utah specimens examined for this study, and the California I. fulva records were determined before the description of I. roguensis . The El Dorado County male was likely collected from Weber Creek, south of Camino, 10 miles (16 km) north of Placerville, where Sandberg (2011b) collected I. marmorata and I. mormona .

Additional Material Examined. COLORADO, Larimer Co., Sand Creek , Ruby Wash, Red Mountain Open Space, 24/ V /2012, B.C. Kondratieff & D. Givens, 5♂, 2♀ ( CSUC); 17/ VI /2012, B.C. Kondratieff & R. Stokes, 10♂, 3♀ ( CSUC) . OREGON, Harney Co., Trout Creek , Whitehorse Ranch Rd 18 mi (29 km) SE Fields, 42.17439°N, 118.43199°W, 20-21/ V /2013, J.B. Sandberg, B.C. Kondratieff, 2♂, 1♀ ( JBSC); GoogleMaps Union Co., Grande Ronde River, Hwy 244, Hilgard Junction State Park ( Hwy 84), 45.34323°N, 118.24013°W, 22/ V /2013, J.B. Sandberg, B.C. Kondratieff, 2♂, 3♀ ( JBSC) GoogleMaps . UTAH, Juab Co., Pole Creek, FR 016 below confluence Pole Canyon, 14/ VI /2012, B.C. Kondratieff & R. W. Baumann, 10♂, 23♀ ( CSUC); Salt Creek, Ponderosa Campground , 14/ VI /2012, B.C. Kondratieff & R . W. Baumann, 2♂, 2♀ ( CSUC) ; Utah Co., Nebo Creek, FR405, 13/ VI /2012, B.C. Kondratieff & R.W. Baumann, 1♂, 8♀ ( CSUC) .


Royal British Columbia Museum - Herbarium


California State University, Chico, Vertebrate Museum


Mykotektet, National Veterinary Institute


Departamento de Geologia, Universidad de Chile














Isoperla fulva Claassen

Sandberg, John B. & Kondratieff, Boris C. 2013

Isoperla fulva

Claassen 1937: 46